HEAT RESISTANT CAST STEEL WITH EXCELLENT HEAT SHOCK FATIGUE RESISTANCE

摘要

PURPOSE:To provide the titled heat resistant cast steel obtained by preparing steel with a specific composition wherein Y alone or combination of Nb.Ti, Nb.Y or Nb.Ti.Y to C, Si, Mn, Cr and Ni is added thereto. CONSTITUTION:Said heat resistant cast steel contains, in the wt% basis, 0.15- 0.60% C, 2.50% or less Si, 2.00% or less Mn, 15-35% Cr, 10-40% Ni and further, contains Y added alone thereto or Nb.Ti, Nb.Y or Nb.Ti.Y added thereto in combination in a range of 0.10-1.00% Nb, 0.05-0.50% Ti, 0.01-0.50% Y. Then, in said cast steel, a sum of a composite added amount of Nb, Ti and Y is 0.11-2.00% and the remainder thereof comprises Fe and inevitable impurities. Because this cast steel is excellent in heat shock fatigue resistance, it can withstand an extremely rapid cooling degree.